Flanged fin



April 5 1927.

I w. B. KLE-MPER'ER FLANGED FIN,

Filed Ju1y30, 1925 Wolfgang 351 921 re},

BY Y

' ATTORNEY Patented Apr. 5, 19:27.

UNITED STATES PATENT oFFlcE- WOLFGANG ZB. KLEHPEBER, OI AKRON, OHIO, AS SIGNOB TO GOODYEAB-ZEPPELIN CORPORATION, OF AKRON, OHIO, A. CORPORATION OF DELAWARE.

' ILANGED rm.

A'pplication filed my 30, 1925. Serial n .-47,o1a.

a novel type of airship fin which possesses.

relativel great efficiency as regards the ratio of weig t to strength of the material of which the fins are formed.

' Another object of my invention is to. provide airship fins which are so reinforced that they are of relatively light weight and are so formed that they tend to.aerodynam1.-

cally enhance the stability of the airship upon which they are employed.-

In the fabrication of structural elements for airships it well known that one of the primary aims is to reduce, as much as posible, the weight of such elements and, at the same time, retain a maximum of strength. Airship fins of the type commonly known are constructed in substantially flat streamline formation and are 'pesitioned vertically ShlP. V

According to the principles of 'my invention I have reinforced the fiii's. by providing them with flanges orsupplemental plane portions disposed at right angles to the ally increasing the resistance offered to the bending load which is exerted on the edge of the fin by the air reaction when air currents strike obliquely against the fins. The flanges also serve as guiding walls to decrease the amount of air overflow escaping around the edges of the fins. from the windward to the leeward side'thereof. Thus the aerodynamical efficiency of the fin is increased and, accordingly, for the same degree of strength and stability, reduction in weight of the fin is secured Furthermore, the flanges positioned vertically upon the top and keel fins 4 assist the hiirizontal fins and? those placed on the horizontal fins assist 'the vertical fins in performing their function. By applying reinforcin flanges to the fins, the distribution of air pressure thereover provides a relatively favorable andmore uniform loading than occurs when conventional fins' are employed. a

For a better understanding ofmy-invention, reference may now be had to the accomorhorizontally adjacent thetail of the air-:

main body portion thereof, thereby materipanying drawings forming a part of this specification, of which;

a I a I I I Fig. 1 1s a fragmentary side-elevatlonal view of an airship provided. with fins embodying my invention;

Fig. 2 is a cross-sectional view of the structure illustrated in Fig, 1, the view being taken substantially along the line III'I ofFig. 1, and parts being omitted for the sake of clearness;

- Fig. 3 is a fragmentary side-elevational view of an'airship provided with fins embodying another form which myinvention ma assume;

lug. 4 1s a cross-sectional view taken substantially along the line IVIV of Fig. 3;

and.

Fig. 5 is a diagrammatical view illustrating graphically the comparative distribution of forces as applied to fins constructed according to my invention and as applied to,

the conventional form of fins.

n practising my invention I have provided vertical fins'10 and horizontal fins 11 secured in a conventional manner to an envelope or hull 12. Each of the vertical fins is formed with a major vertically extending portion 13 and a supplemental portion '14, the latter consisting of flanges 15 extending along the outer edge of the fins at substantially right angles thereto. Itwill be observed that the fins as a whole are of T- shape in cross-section. At the rear end of the fins 10, the usual rudders 16 are provided.

Each of the'horizontal fins 11 is constructed tofor m a major substantially horizontally extending portion 16 and is provided with supplemental portion 17, consisting of vertically disposed flanges 18, similar to the vertical fins 10. Each fin 11 is provided with a conventional rudder 19. It will be the flanges are ofstreamline form.

observed that all of the major portions and illustrated in Figs. 3 and 4, vertical and horizontal fins 20 and 22, respectively, of

streamline form, are secured to an envelope or hull 2 3 of an airship and are rovided with flanges 24'and' 25, respective y, positioned adlacent the edges of the fins and at right-ang es thereto.; -v In this form of my invention the major portions 26 and 27 of the fins 2Q and 22, respectively, are substan tially 51111111111) portionsp13 and 16, respectively, shown in Figs. 1 and 2, but the flanges 24 and 25 in this instance are spaced; from the outer edges of the fins so'as-to define a cruciform configuration in cross-section. Rudders 28 and 29 are likeWise-secured-to the fins 26 and 27, respectively. 1 I

The flanges 24 and 25 ar" preferably a'r ranged substantially parallel to the natural airflow lineswhich occur at the zero angle of air attack of the airship, i. c. When" the airship proceeds on an even keel. However, it is to be understoodthat'the airflow line direction at the location of these flanges may have a slight converging angle to the axis of the airship. If for any reason the fin would have to be so designed that its outer edge'could not follow the airflow line direction along a suflicient length thereof, the

flange might depart from the edge at a certain point and follow the airflow lines of no incidence along a suflicient length without however deviating too far from the edge contour of the fin, in order to retain a proper efliciency as a border overflow protection.

In order to more clearly explain the advantages of my invention over the plain form finof conventional construction, reference may be had to Fig. 5. As illustrated in this-figure by a curved graph 30, a fin constructed without a flange, asindicated in dot and dash lines at 30", is subjected to severe stresses at the edges thereof, as'indi: cated by the peak of the load at 31. These stresses are caused by the strong eddy washing around the fin from the windward to the leeward side. On the other hand, the

stresses upon a fin constructed with flanges,

'as' 'indicated in dot and dash lines at 32*,

are represented by a curved graph 32. The highest point indicating the greatest load peak at 33, is materially lower than the point .31 representing the point of greatest stress in the non-flanged fin.

-. ."It will be notedthat the flanges included in my inventionare preferably applied to fixed-fins,--while the relatively movable parts i of the airship, such as rudders and elevators, are:'--of minor importance with respect to the edge stresses,-as well-as to'the overflow protection. This is true because the area ofthe fixed finsris much greater than that of the movable surfaces and-theyhave'a ininor aspect ratio. Even when the rudders 4 are inclined,:} the greatest strain resulting from aifreactio'n occurs upon the fixed fins in front of the rudders.

' From the foregoing description it will be apparent that I have provideda materially improvedform of fin which is simple in construction and which performs the function of stabilizingthe aircraft with relatively more efficiency than 'in any of the heretofore known structures.

Although I have illustrated buttwo preferred forms which my invention may as.- sume and have described those forms in detail, itwill be apparentto thoseskilled in the art that the invention'is not so'limited but that various minor modifications and changes may be made therein w thout departing from the spirit of my invention or from the scope of the appended claims.

to the covering and a plurality of plane portions disposed substantially at right angles to the first named plane portions.

3. In an airship having anelongate hull,

a fin of substantially T-shape cross-section rigidly secured adjacent one end thereof.

4. In an elongate aircraft, a .fin' rigidly secured thereto comprising a major plane portion and a minor integral portion, the combination of the portions defining a substantially T-shape in cross-section.

5. A stabilizing member forla lighter than-airship provided with a'hullcompris- .ing a plane portion rigidly secured to the hull and supplemental flanges following the air flow lines of no incidence. i

6. An aircraft fin formed with supplemental flanges slightly converging towardthe stern of the aircraft.

7. AIstabilizing-"member for 'a lighterthan-ai'rship provided with a hull compris inga fin of substantiallycruciform crosssection rigidly secured to the hull.

- Infwitness whereof, I have hereunto signed my name.

' WOLFGANG n. KLELiPsnnR. 

